Abstract: A typical soft rock foundation deformation case of nuclear island in China is analyzed in this paper. Two-dimensional as well as three-dimensional finite element models of the nuclear island foundation are established. The uncertainty of the distribution of strongly weathered rock mass within moderately weathered rock mass beneath the nuclear island foundation and the uncertainty of key geotechnical parameters were considered in the numerical models. The influence of the layered rock mass distribution on deformation parameters is also considered. The foundation deformation of the nuclear island was estimated and analyzed comprehensively. The total and differential settlement of the soft rock foundation for the nuclear power plant are obtained, and the estimation and analysis methods are compared in the paper. The analysis results show that the maximum total and differential settlements of the nuclear island foundation meet the design and specification requirements. The distribution of the strongly weathered rock under the nuclear island foundation has less influence on the maximum settlement of the foundation. The proposed estimation and analysis methods for the soft rock underneath the nuclear island foundation can be used for the subsequent settlement estimation and analysis of similar projects.

Key words: Soft Rock, Nuclear Island Foundation, Foundation Deformation, 3D Finite Element Model